The present invention relates to fuel rails for internal combustion engines.
Previously, known fuel rails have been formed from low carbon tubular steel. The steel tube was then pierced in several predetermined locations to allow other components to be inserted into the tube, such as fuel cups, hose fittings, and other tubes. At this point, mounting brackets were spot welded onto the tube. A copper paste was applied to joints between the components and the tube. The tube and the attached components were then sent through a brazing furnace to melt the copper at each joint, forming a hermetic, leak-proof seal. This brazing process caused several problems. First, during brazing, the entire tube would severely warp, requiring the tube or the components to be bent into proper position later in the manufacturing process, adding extra steps to the manufacturing process. Second, the brazing process was somewhat unreliable, resulting in leaks in the brazed joints.
To the inventors"" knowledge, other fuel rails have been formed from two shells which are brazed together, but these rails suffer the same deficiencies as described above.
It would be beneficial to develop a fuel rail which does not warp during manufacture, and in which a tight seal can be formed between components.
Briefly, the present invention provides a fuel rail. The fuel rail comprises a first portion including a generally elongated base, at least one mounting bracket and a plurality of fuel cup openings in the generally elongated base. The fuel rail also comprises a second, generally U-shaped, portion having a first and second opposing sides. Each of the first and second opposing sides are sealingly connected to the generally elongated base with a laser weld. The second portion also has a supply end having a fuel supply opening, and a closed end, distal from the supply end. The closed end and the supply end are sealingly connected to the generally elongated base with a laser weld.
The present invention also provides a fuel rail assembly. The fuel rail assembly comprises a fuel supply header having a discharge end and a fuel rail connected to the discharge end of the fuel supply header. The fuel rail includes a first portion including a generally elongated base, at least one mounting bracket and a plurality of fuel cup openings in the generally elongated base. The fuel rail also includes a second, generally U-shaped, portion having a first and second opposing sides. Each of the first and second opposing sides is sealingly connected to the generally elongated base with a laser weld. The second portion also has a supply end having a fuel supply opening, and a closed end, distal from the supply end. The closed end and the supply end are sealingly connected to the generally elongated base with a laser weld. The assembly also includes a plurality of fuel injectors, with each of the plurality of fuel injectors being connected to a fuel cup opening,
The present invention also provides a method of manufacturing a fuel rail. The method comprises forming a first portion having at least one integral mounting bracket; a deep drawing a second, generally U-shaped portion having first and second opposing sides, a closed end and a supply end; and sealingly connecting the first and second opposing sides, the closed end, and the supply end to the first portion.